Note: Descriptions are shown in the official language in which they were submitted.
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SCREEN ASSEMBLY AND SHALE SHAKER
The present invention relates to a screen assembl
for use in a shale shaker and a shale shaker.
In the drilling of a borehole in the construction of
an oil or gas well, a drill bit is arranged on the end of
a drill string and is rotated to bore the borehole. A
drilling fluid known as "drilling mud" is pumped through
the drill string to the drill bit to lubricate the drill
bit. The drilling mud is also used to carry the cuttings
produced by the drill bit and other solids to the surface
through an annulus formed between the drill string and
the borehole. The drilling mud contains expensive
synthetic oil-based lubricants and it is normal therefore
to recover and re-use the used drilling mud, but this
requires the solids to be removed from the drilling mud.
This is achieved by processing the drilling fluid. The
first part of the process is to separate the solids from
the solids laden drilling mud. This is at least partly
achieved with a vibratory separator, such as those shale
shakers disclosed in US 5,265,730, WO 96/33792 and WO
98/16328.
Shale shakers generally comprise an open bottomed
basket having one open discharge end and a solid walled
feed end. A number of rectangular screens are arranged in
the basket, which are held in C-channel rails located on
the basket walls, such as those disclosed in GB-A-
2,176,424. The basket is arranged on springs above a
receptor for receiving recovered drilling mud. A skip or
ditch is provided beneath the open discharge end of the
basket. A motor is fixed to the basket, which has a drive
rotor provided with an offset clump weight. In use, the
motor rotates the rotor and the offset clump weight,
which causes the basket and the screens fixed thereto to
shake. Solids laden mud is introduced at the feed end of
the basket on to the screens. The shaking motion induces
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the solids to move along the screens towards the open
discharge end. Drilling mud passes through the screens.
The recovered drilling mud is received in the receptor
for further processing and the solids pass over the
discharge end of the basket into the ditch or skip.
The screens are generally of one of two types: hook-
strip; and pre-tensioned.
The hook-strip type of screen comprises several
rectangular layers of mesh in a sandwich, usually
comprising one or two layers of fine grade mesh and a
supporting mesh having larger mesh holes and heavier
gauge wire. The layers of mesh are joined at each side
edge by a strip which is in the form of an elongate hook.
In use, the elongate hook is hooked on to a tensioning
device arranged along each side of a shale shaker. The
shale shaker further comprises a crowned set of
supporting members, which run along the length of the
basket of the shaker, over which the layers of mesh are
tensioned. An example of this type of screen is disclosed
in GB-A-1,526,663. The supporting mesh may be provided
with or replaced by a panel having apertures therein.
The pre-tensioned type of screen comprises several
rectangular layers of mesh, usually comprising one or two
layers of fine grade mesh and a supporting mesh having
larger mesh holes and heavier gauge wire. The layers of
mesh are pre-tensioned on a rigid support comprising a
rectangular angle iron frame and adhered thereto. The
screen is then inserted into C-channel rails arranged in
a basket of a shale shaker. An example of this type of
screen is disclosed in GB-A-1,578,948.
A further example of a known rigid support is
disclosed in PCT Publication No. WO 01/76719, which
discloses, amongst other things, a flat panel like
portion having apertures therein and wing portions which
are folded to form a support structure, which may be made
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from a single sheet of material. This rigid support has
been assigned the Trade Mark "UNIBODY" by the applicants.
US-A-4,575,421 discloses a screen assembly having a
perforate rigid plate having two layers of mesh adhered
thereto and two hook strips provided on either side to
facilitate attachment in a shale shaker provided with a
plurality of stringers over which the screen assembly is
crowned. The rigid plate is rigid in terms of maintaining
some tension in the screening material, but would
nonetheless flex when held between the hook strips.
The layers of mesh in the screens wears out
frequently and therefore needs to be easily replaceable.
Shale shakers are generally in the order of 5ft wide and
lOft long. A screen of dimensions 4ft wide by lOft long
is difficult to handle, replace and transport. It is
known to use two, three, four or more screens in a single
shale shaker. A standard size of screen currently used is
of the order of 4ft by 3ft.
US-A-4,582,597 discloses a vibratory separator
having a basket and channels arranged on internal faces
of the basket for receiving the two sides of a screen
assembly. An inflatable hose is arranged in the channels.
The screen assembly comprises screening mesh laid over
and fixed to a frame. The screen assembly is slid into
the channels in the vibratory separator. The hose is
inflated using a pneumatic fluid to force the frame of
the screen assembly to assume a crowned centre, in order
to reduce whipping.
GB-A-2,176,424 discloses a vibratory separator having
a basket and channels arranged on internal faces of the
basket for receiving a screen assembly and a clamping
device. The screen assembly comprises screening mesh laid
over and fixed to a frame. The clamping device comprises
a frame of similar dimensions to the frame of the screen
assembly. The frame has an inflatable stocking thereon,
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which is attached to pneumatic or hydraulic fluid supply
means. When both the screen assembly and the clamping
device are slid into the channels, the stocking is
inflated to fix the screen assembly in the channels.
There is also disclosed a clamping device having an
intermediate frame member on which a tributary of the
stocking is arranged. Support members are provided above
and below the screen assembly so that, in use the
tributary is inflated to clamp the screen assembly
between the supports.
GB-A-2,176,425 discloses a vibratory separator
having a basket and channels arranged on internal faces
of the basket for receiving a screen assembly. The screen
assembly comprises screening mesh laid over and fixed to
a frame. The channels have an inflatable stocking therein
for clamping the frame of the screen assembly in the
channels. The screen assembly also has a stiffening rib
along each of two intermediate parts of the screen
assembly and the vibratory separator has a tributary of
the stocking along each of two intermediate parts of the
vibratory separator, such that in use, the tributaries
are inflated to engage the stiffening ribs.
US-A-4,809,791 discloses a shaker having a screen.
The screen is supported on flexible transverse arch-
shaped beams attached to the sides of a frame. A ram is
arranged in the shaker and is attached to the centre of
the flexible transverse arch-shaped beam. The ram is
extended to increase the tension in the screen.
It is important to achieve maximum screening area in
a given space and to obviate the need for mechanisms for
fixing screen assemblies to shakers which blind areas of
the screening material and which will decrease the screen
assembly's screening capacity.
The present invention also attempts to provide a
panel for a screen, which will increase the life of
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layers of screening material arranged thereon.
In accordance with the present invention, there is
provided a screen assembly for a shale shaker, the screen
assembly comprising a support and at least one layer of
screening material, the support having a periphery and an
underside characterised in that a spacer is arranged on
the underside of the support.
Preferably, the support comprises two opposed sides and a
support member extending between the sides, wherein the
spacer is arranged underneath the support member.
Advantageously, the spacer extends substantially the
entire length of the support member. Alternatively, the
spacer may be shorter or longer. Preferably, the support
is generally rectangular.
Advantageously, the support comprises a frame.
Preferably, the frame comprises support members made from
tubing. Preferably square section or round section. The
cross-member preferably, has a cross-member width and the
generally flat side of the body has a body width and the
body width is substantially equal to the cross-member
width.
Alternatively, the support is of the type having a
body member made of a single integral sheet-like
material, said body member having a first portion and a
second portion, said first portion having a plurality of
rib supports bent or folded out from spaced apart
openings, slots or cuts of said first portion, the second
portion having at least one opening therethrough bent or
folded over onto the first portion so that the underside
of the second portion contacts top surfaces of the rib
supports, the spacer arranged underside of the support.
Preferably, the spacer comprises a seal.
Advantageously, the support comprises a cross-member
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within the periphery of the support, the spacer arranged
on the cross-member. Preferably, the support comprises a
plurality of cross-members.
Preferably, the spacer has a body defining generally
a "D" shaped. Advantageously, the spacer is hollow.
Alternatively, the spacer has a solid body. The spacer
may rap around the support member and may form a lip. The
spacer may be arranged in a recess in the support. The
support member may have a series of openings
therethrough, and may form a truss-like rib. Cutouts,
which may be triangular openings in the rib may form the
truss-like configuration. Preferably, the spacer is
secured to the underside of the support by at least one
of the following: glue; a friction fit between the spacer
and the support.
Preferably, the screen assembly further comprises a
seal on the periphery of the screen assembly for seal
between an abutting screen or part of a shale shaker
forming an interface. Preferably, on end faces of the
ends of the screen assembly and/or side faces of the
sides of the screen assembly.
Preferably, the spacer is a generally rectangular
cross-section which is about 2cm (3/4") long and about
1cm (3/8") high. The spacer may be within one or two cm
larger than these dimensions.
Preferably, the support has at least one hole for
receiving an upwardly projecting member projecting
upwardly from the mounting structure of the shale shaker.
Advantageously, the spacer is arranged within the
periphery of the support. Preferably, not only on the
peripheral support members.
Advantageously, the screen assembly comprises a
further layer of screening material.
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Preferably, the spacer is arranged substantially
around the entire periphery of the support.
The present invention also provides a shale shaker
comprising a screen assembly of the invention, wherein
the shaker comprises fixing apparatus for fixing the
periphery of the screen assembly and a structural members
underneath the screen assembly, characterised in that the
spacer is arranged between the screen support and the
structural member. Preferably, the structural members are
arranged underneath the screen assembly and within the
periphery thereof.
The present invention also provides a method for
treating material with a shale shaker, the method
comprising the steps of introducing material to be
separated into the shale shaker of the invention,
vibrating the screen assembly to separate the material.
Preferably, the material is solids laden drilling mud.
The present invention also discloses, in at least
certain embodiments and certain aspects, a screen
assembly for mounting on mounting structure or deck of a
vibratory separator or shale shaker, the screen assembly
having a frame with a first frame end spaced apart from a
second frame end by two opposed spaced-apart sides
including a first side and a second side, the frame
having a top and a bottom, the frame abutting the
mounting structure or deck at a mounting-structure/frame
interface, screening material on the frame, and seal
apparatus on the frame for sealing the mounting-
structure/frame interface.
The present invention, in certain aspects, discloses
methods for mounting a screen assembly to a screen
mounting structure of a vibratory separator to facilitate
sealing of an interface between the screen assembly and
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the screen mounting structure, the method including
locating the screen assembly on the screen mounting
structure so that all cross-members of a support
supporting screening material of the screen assembly are
all either generally transverse to or all generally
parallel to the a direction of material flow from one
side of the screen assembly to the other, or at least two
exterior sides of the support are independent along their
entire lengths without connection between an exterior
side and a cross-member that extends across the support
parallel to the side (i.e., there may be one or more
transverse cross-members extending between two
longitudinal cross-members, but such transverse cross-
members do not connect with the exterior sides of the
support), and forcing first and second sides of the
support down with crowning apparatus to effect crowning
of the screen assembly, third and fourth sides (the sides
which have no connection to the transverse cross-members)
which are at right angles to the first and second sides
rigid yet sufficiently flexible so that with the screen
assembly in a crowned configuration the third side and
the fourth side each along substantially all of the
length thereof sealingly contact a surface of the screen
mounting structure, In certain embodiments of the present
invention a screen assembly is disclosed in which a
honeycomb structure serves as a support member for screen
mesh material.
Such screen assemblies which have relatively less
material than certain prior art screen assemblies, yet
which are sufficiently strong and stable for effective
use; Such screen assemblies with one or more spring
members in a support for screening material.
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For a better understanding of the present invention,
reference will now be made, by way of example, to the
accompanying drawings, in which:
Figure 1A is an underneath view of a support for a
screen assembly in accordance with the present invention;
Figure 1B is a view in cross-section taken along line 1B-
1B of Figure 1A;
Figure 2 is an underneath view of part of support
for a screen assembly in accordance with the present
invention;
Figures 3A, 3B, and 3C are views in cross-section of
alternative parts of a support for a screen assembly in
accordance with the present invention;
Figures 4A and 4B are side views in cross-section of
seals and seal holders for use in a screen assembly in
accordance with the present invention;
Figures 5A to 5D are side cross-section views of
seal structures in accordance with the present invention.
Figure 6A is a top view of a screen assembly in
accordance with the present invention; Figure 6B is an
underneath view of the screen assembly shown in Figure
6A;
Figure 6C is an end view and Figure 6D is a side
view of the screen assembly shown in Figure 6A;
Figure 7 is a perspective view of a shale shaker in
accordance with the present invention;
Figure 8 is a view in cross-section of a seal member
arranged on a frame member forming part of a screen
assembly in accordance with the present invention;
Figure 9A is a top view of a frame for a screen
assembly in accordance with the present invention; Figure
9B is a view in cross-section taken along line 9B-9B of
Figure 9A; Figure 9C is a view in cross-section taken
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along line 9C-9C of Figure 9A;
Figure 10A is a top view of a frame for a screen
assembly in accordance with the present invention; Figure
lOB is a side view of the screen assembly shown in Figure
1OA; Figure lOC is an end view of the screen assembly
shown in Figure 10A; Figure 10D is a view in cross-
section taken along line 10D-10D of Figure 10A; Figure
10E is a view in cross-section taken along line 10E-10E
of Figure 10A; Figure 1OF is a side view in cross-section
of a cross-member of the screen assembly shown in Figure
10A;
Figure 11A is a top view of a frame for a screen
assembly in accordance with the present invention; Figure
11B is a side view of a cross-member of the screen
assembly shown in Figure 11A; Figure 11C is a side view
of an alternative cross-member for the screen assembly
shown in Figure 11A;
Figure 12 is a view in cross-section of a member for
a screen assembly in accordance with the present
invention;
Figure 13A is a side view of a prior art shale
shaker; Figure 13B is a top view of the shale shaker
shown in Figure 13A; Figure 13C is a side view in cross-
section of the shaker shown in Figure 13A; Figure 13D is
a view of part of the shale shaker shown in Figure 13C;
Figure 13E is a view of a part of the shale shaker shown
in Figure 39A; and
Figure 14 is a view in cross-section of part of a
support having a space maintainer for a screen assembly
in accordance with the present invention.
Referring to Figures 1A and 1B, there is shown a
support for use in a screen assembly 300 in accordance
with the present invention which has two end members 301,
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302 spaced apart by two side members 303, 304. Two
optional spaced-apart cross-members 305, 306 extend
between the two end members 301, 302 and two optional
spaced-apart cross-members 307, 308 extend between the
cross-members 305, 306. The end members, side members,
and/or cross-members may be solid or they may be hollow.
As shown in Figure 1B a side member 303 is a hollow
tubular member as is commonly used in supports for screen
assemblies for vibratory separators and shale shakers.
One, two, three or more layers of screening material (not
shown) may be provided to form a screen combination (not
shown). The layer of screening material may be glued or
sewn together. The screen combination may further
comprise a supporting mesh (not shown). The supporting
mesh may be glued, epoxied, sewn or otherwise attached to
the screen combination. The screen combination or
supporting mesh may be adhered, epoxied, sewn or
otherwise attached to the support to form a complete
screen assembly. A perforate plate may also be used to
support the screen combination and/or supporting mesh and
may be bonded thereto. The perforate plate may be bonded
to the support or simply placed over the support and
fixed to the support in a fixing mechanism in a shale
shaker, such as a pneumatic bladder, such as the one sold
by the applicants under the trade name "PNEUMO-SEAL",
thus forming a screen assembly in the shale shaker.
As shown in Figure 1A seal members 311 - 314 are
affixed to underneath surfaces of the end members 301,
302 and the side members 303, 304 to seal an interface
between a screen assembly with a support 300 and a deck
or mounting surface of a vibratory separator or shale
shaker. Optionally, either the seal members 311, 312 or
the seal members 313, 314 are deleted. Any suitable seal
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members, including any seal disclosed herein in
accordance with the present invention, may be used for
the seals 311 - 314; and, as shown in Figure 27B, in one
aspect the seal 314 is "D" shaped with a hollow interior
315 which facilitates flexing of the seal to enhance
sealing against a shaker deck or other screen mount or
support. In one aspect the seals are made of nitrile
material.
As shown in Figure 2 a screen support 310 (or any
support in accordance with the present invention) may
have exterior seals around its periphery like the seals
316, 317 shown on an end member 301 and a side member 303
(shown partially; seals extend completely around
support). As with the bottom seals 311 - 314, any pair
of two of the peripheral seals may be deleted. The seals
316, 317 may be solid or hollow with any shape shown or
referred to herein.
Figure 3A shows a seal 320 (similar to the seal 260
described above) secured to a screen assembly support
part 321. Optionally, the seal 320 has a void space 322
which enhances seal/screen deck contact and, also
optionally, a corrugated surface 324 for contacting a
surface for sealing. Any seal structure in accordance
with the present invention may be made of any suitable
plastic, metal, rubber, composite, fiberglass, alloy or
seal material.
Figure 3B shows a seal 330 (similar to the seal 280
described above) secured to a screen assembly support
332. The seal 330 has a lip 334 for abutting a surface
to be sealed against. A wall 335 connects the lip 334 to
a base part 336 of the seal 330. Optionally a void space
337 extends throughout the length of the seal 330 to
enhance flexibility. Any seal or seal member in
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accordance with the present invention may have a void
space like the void space 337 of a cross-sectional shape
similar to or different than that of the void space 337
(e.g., oval, circular, square).
Figure 3C shows a seal 340 on a support part 342.
The seal 340 has a hemispherically-shaped head 344
projecting from a base 346.
A seal like the seals 311 to 314 on the screen
support 300 helps inhibit unscreened fluids from flowing
beneath a screen assembly and a shaker deck (or other
mount or screen assembly support). The seals also
prevent a metal screen support from directly contacting a
metal screen mounting structure, reducing metal-to-metal
wear. Any suitable fasteners, connectors and/or
adhesives or glues may be used to secure a seal in
accordance with the present invention to a frame or
screen support. In one particular aspect LOCTITE
(trademark) adhesives are used to adhere the seals to a
screen support.
Figure 4A shows a seal holder 240 in accordance with
the present invention which has a lower part 241a, an
upright part 241b, and a top part 241c projecting
downwardly. A seal 242 has a body 243 releasably and
removably disposed in an interior space of the seal
holder 240. Optionally, the body 243 is hollow as shown
(or it may be solid). A lip 244 is connected to or
formed integrally of a projecting part 245. The
projecting part 246 is connected to or formed integrally
of the body 243. The seal holder 240 can be used in a
vibratory separator or shale shaker. Preferably the
shape of the interior space of the seal holder 240 and of
the body 243 of the seal 242 are substantially the same.
The lip 244 is optional. Preferably the seal 242 is
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flexible to enhance its sealing effect against the end of
a screen assembly. The top part 241c of the seal holder
240 projects into a recess 246 formed between the lip 244
and the body 243 of the seal 242. This assists in
maintaining the seal 242 in a desired position with
respect to the end of a screen assembly. Such seal
holders may be suitable for the one or both ends of the
screen to seal between abutting screens and for abutting
a surface in the shale shaker. The seals shown in Figure
1A to 3C are used in conjunction with the seal holders
shown in Figures 4A and 4B.
Figure 4B shows a seal holder 247 in accordance with
the present invention which has a lower part 247a, an
upright part 247b, and an inclined part 247c projecting
upwardly. A seal 248 has a body 248a releasably and
removably disposed in an interior area of the seal holder
247. Optionally, the body 248a is hollow as shown (or it
may be solid). A lip 249 is connected to or formed
integrally of a projecting part 248b. The projecting
part 248b is connected to or formed integrally of the
body 248a. The seal holder 247 can be used in a
vibratory separator or shale shaker as the seal holder
22. Preferably the shape of the interior space of the
seal holder 247 and of the major portion of the body 248a
of the seal 247 are substantially the same. The lip 249
is optional. Preferably the seal 282 is flexible to
enhance its sealing effect against the end of a screen
assembly. The inclined part 247c of the seal holder 247
projects into a recess 248c formed between a lower part
248d of the lip 249 and the body 248a of the seal 248.
This assists in maintaining the seal 248 in a desired
position with respect to the end of a screen assembly.
In one aspect the lip 249 is flexible with respect to the
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projecting part 248b and can move backwardly (to the left
in Figure 30B) to accommodate a screen assembly end
and/or to enhance sealing contact therewith.
It is within the scope of this invention for a
screen assembly with a seal structure in accordance with
the present invention (as is the case for any of the
screen assemblies disclosed herein) to be any known
screen assembly that abuts an end, side, or surface of a
vibratory separator or shaker; and for the screening
material to be any known screening material of one or
more layers, with or without support, with or without
layers connected together, which are generally flat or
undulating.
Figure 5A shows a seal 250 removably mounted in a
seal holder 251 with a screen assembly 252 (shown
schematically) having an end 253 sealingly contacting the
seal 250. The seal 250 has a lip 254 that abuts an
exterior surface 255 of the seal holder 251. The screen
assembly 252 has screening material 256. The seal 250 is
of a length substantially equal to or slightly larger
than a length of the end 253. The seal holder 251 is
secured to, connected to, or formed integrally of a side
wall 257 of a basket or other screen supporting structure
of a separator or shaker.
Figure 5B shows a seal 260 removably mounted to a
seal holder 261 with a screen assembly 262 (shown
schematically) having an end 263 sealingly contacting the
seal 260. The seal 260 has a recesses 264 that receive
portions 265 of the seal holder 261. The screen
assembly 262 has screening material 266. The seal 260 is
of a length substantially equal to or slightly larger
than a length of the end 263. The seal holder 261 is
secured to, connected to, or formed integrally of a side
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wall 267 of a basket or other screen supporting structure
of a separator or shaker. Optionally, the seal 260 has a
void space 268 which enhances seal/screen assembly
contact and, also optionally, a corrugated surface 260a
for contacting the screen end 263. Optionally a member
269 may be permanently or removably positioned within the
seal holder 261 to serve as a space maintainer, shock
absorber, cushion, and/or seal and may be made of any
suitable plastic, metal, composite, fiberglass, alloy or
seal material.
Figure 5C shows a seal 270 removably mounted in a
seal holder 271 with a screen assembly 272 (shown
schematically) having an end 273 sealingly contacting the
seal 270. The seal 270 has a lip 274 that abuts a
surface 275 of a seal holder 279. The seal holder 279 is
removably or permanently positioned within a seal holder
271. The screen assembly 272 has screening material 276.
The seal 270 is of a length substantially equal to or
slightly larger than a length of the end 273. The seal
holder 271 is secured to, connected to, or formed
integrally of a side wall 277 of a basket or other screen
supporting structure of a separator or shaker. The seal
holder 279 may be made of any material mentioned above
for the member 269. Optionally the seal holder 279 may
have a corrugated outer surface 279a to facilitate its
movement within the seal holder 271. A recess 279b
receives a lip 274 of the seal 270. A wall 275 connects
the lip 274 to an outer part 278 of the seal 270.
Optionally, the seal 270 has an inner void space 270a.
Figure 5D shows a seal 280 removably mounted in a
seal holder 281 with a screen assembly 282 (shown
schematically) having an end 283 sealingly contacting the
seal 280. The seal 280 has a lip 284 that abuts an
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exterior surface 285 of the seal holder 281. The screen
assembly 282 has screening material 286. The seal 280 is
of a length substantially equal to or slightly larger
than a length of the end 283. The seal holder 281 is
secured to, connected to, or formed integrally of a side
wall 287 of a basket or other screen supporting structure
of a separator or shaker. A recess 281b receives a lip
288 of the seal 280. A wall 289 connects the lip 281b
to an outer part 281c of the seal 280. A rigid member
280d extends throughout the length of the seal 280 to
provide strength and rigidity. .
Any seal or seal member according in any embodiment
of the present invention may have a rigid member like the
rigid member 280d of a cross-sectional shape similar to
or different than that of the rigid member 80d (e.g.,
oval, circular, square).
The seal holders of Figures 5A - 5D have a length
corresponding to the length of the seals mounted therein
or thereto (e.g. slightly shorter, slightly larger or
similar to that of the seals) . The seal preferably has a
length equal to the length of the end member of the
support for the screen assembly, or at least over a
portion of the length of the end member which requires a
sealing to be effected.
Figures 6A - 6F show a screen assembly 940 in
accordance with the present invention which has a tubular
frame 942 with end members 944 and interconnected side
members 945. A screening material layer or combination
of layers 950 is secured to the tubular frame 942, e.g.
with glue, adhesive, epoxy, and/or fasteners. An
optional cross-member 941 (of a plurality of optional
spaced-apart cross-members 943 that extend between and
have ends connected to the sides 945) has two optional
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notches 946, either of which is for receiving a portion
of an upstanding member of a shale shaker deck. As shown
in Figure 6B, the frame 942 is surrounded with seal
members 970 - 973 which are secured to the frame 942 with
any suitable glue, adhesive, epoxy, and/or fasteners. In
one aspect the seal members 970 - 973 are hollow with a
general "D" shape with the flat part of the "D" adhered
to the frame 942, in one particular aspect, with LOCTITE
(trademark) brand commercially available adhesives, e.g.
LOCTITE (trademark), TAK PAK (trademark) adhesives, PRISM
(trademark) adhesives, or SUPER BONDER (trademark)
adhesives; and, in one particular aspect, the seal
members 970 - 973 are made of Nitrile material (which can
withstand the heat and chemical composition of drilling
materials pumped from a wellbore).
As shown in Figures 6A to 6D, optionally the seal
members 971, 973 have holes 975 corresponding to and
aligned with holes 974 in the frame 942 (holes 974 shown
in dotted lines in Figures 6A, 6C, 6D). The holes 974,
975 are sized, configured and located for receiving an
upwardly projecting member projecting upwardly from a
screen mounting structure or deck of a shaker or
vibratory separator. Optionally, one of the holes 974 is
deleted.
Figure 7 shows a shale shaker 990 with a plurality
of spaced-apart upwardly projecting members 902
projecting up from a deck 992. It is to be understood,
although not shown, that as desired, upstanding members
902 may be provided spaced-apart on both sides or around
the entire periphery of the deck 992 (or of any vibratory
separator or shaker deck). Optionally, holes 993 may be
deleted or they may be provided and sized for receiving
downwardly projecting members of a screen assembly. In
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one particular aspect the upstanding members 902 are
sized and located for receipt within holes like the holes
974, 975 of the screen assembly 940, Figures 6A to 6D.
Optionally, only one upstanding member 902 is provided
for each screen assembly.
Thus it is seen, e. g. as shown in Figures 6A to 7,
that the present invention provides a screen assembly for
releasable mounting to a mounting structure of a
vibratory separator or shale shaker, the mounting
structure with a body over which a screen assembly is
positionable, part of material to be treated flowable
through the body, at least one upwardly projecting member
projecting upwardly from the body, the at least one
upwardly projecting member sized and configured so it is
receivable in a corresponding hole in the screen
assembly, the at least one projecting member having a
projecting member cross-sectional area, the screen
assembly having a support (e.g. a frame); screening
material on the support (e.g. one, two, three or more
layers); the support two spaced-apart ends, the two
spaced-apart ends spaced-apart by two spaced-apart sides,
each of the two spaced-apart sides connected to each of
the two spaced-apart ends, optionally one or a plurality
of spaced-apart cross-members extending between the two
spaced-apart sides from one side to the other side, at
least part of the support being a tubular member with a
top and a bottom, a portion of the screening material
over the tubular member; at least one hole in the bottom
of the tubular member, the at least one hole sized,
configured, and located for receiving the at least one
upwardly projecting member of the body of the mounting
structure, the at least one hole having a hole cross-
sectional area greater than the projecting member cross-
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sectional area.
Thus it is also seen, e.g. as shown in Figures 6A to
7, that the present invention provides a shale shaker
system for separating components of drilling fluid with
solids entrained therein, the shale shaker system having
a base; a screen mounting basket on the base; vibrating
apparatus connected to the screen mounting basket for
vibrating the screen mounting basket; the screen mounting
basket having mounting structure for at least one screen
assembly mounted on the mounting structure, the mounting
structure having a body over which the at least one
screen assembly is positionable, part of the drilling
fluid to be treated by the shale shaker flowable through
the at least one screen assembly and through the body; at
least one screen assembly mounted on the mounting
structure; the at least one screen assembly releasably
mounted to the mounting structure of a shale shaker; the
mounting structure having at least one upwardly
projecting member projecting upwardly from the body, the
at least one upwardly projecting member sized and
configured so it is receivable in a corresponding hole in
the screen assembly; the at least one projecting member
having a projecting member cross-sectional area; the at
least one screen assembly including a support; screening
material on the support; the support being a frame with
two spaced-apart ends, the two spaced-apart ends spaced-
apart by two spaced-apart sides, each of the two spaced-
apart sides connected to each of the two spaced-apart
ends, the frame optionally having one or a plurality of
spaced-apart cross-members extending between the two
spaced-apart sides from one side to the other side, at
least part of the frame being a tubular member with a top
and a bottom, a portion of the screening material on top
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of the tubular member; and at least one hole in the
bottom of the tubular member, the at least one hole
sized, configured, and located for receiving said at
least one upwardly projecting member of the body of the
mounting structure, the at least one hole having a hole
cross-sectional area greater than the projecting member
cross-sectional area.
Figure 8 shows a seal member 980 in accordance with
the present invention which may be used in place of or in
combination with any seal or seal member disclosed herein
for sealing a support/mounting-structure interface. The
seal member 980 has a corrugated structure (as viewed in
cross-section in Figure 8) and, in accordance with the
present invention, such a seal member may have any
desired member of ridges and valleys. In one aspect, the
seal member 980 is made of a single sealing material;
but, as shown, the seal member has multiple layers 981 -
983. In one aspect these layers are of differing
flexibilities with the layer 981 most flexible, the layer
982 less flexible, and the layer 983 least flexible.
Optionally, any one or two layers are deleted. Adhesive,
glue, or epoxy 985 - 987 secures the seal member 980 to a
frame member 984.
Figures 13A - 13E illustrate a prior art shale
shaker SH which has a four screen assembly mounting
structures M each of which has two crossbars C. Cross-
members of screen assemblies (e.g. see the screen support
in Figure 1A) mounted on the mounting structures M are
often located and positioned to abut the crossbars C.
Use of peripheral seals around the bottom of a screen
assembly support or frame (e.g. see the seal members 311
- 314, Figure 1A) can effectively raise a screen assembly
with respect to a mounting structure or deck; e.g. in one
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particular aspect a three-eights inch gap is created
between parts of a mounting structure or deck and the
bottom of a support or frame. With such a gap present a
screen assembly can flex repeatedly in use resulting in
damage to the screen assembly and a shortened screen
assembly useful life. In the prior art, to remedy this
situation, pieces of resilient material called "crown
rubbers" (see crown rubber R, Figure 13E) are placed on
the crossbars C which fill the gap and maintain contact
with the bottom of the screen assembly, e.g. with cross-
members as in Figure 1A. The crown rubbers R are made of
urethane or nitrile.
Problems have arisen related to the use of the crown
rubbers. Over time the crown rubbers wear and need to be
replaced. If they are not replaced regularly, a gap can
be formed between the crown rubbers and the bottom of a
screen assembly. This gap allows the screen assembly to
flex inordinately resulting in damage to the screen
assembly and shortened screen assembly life.
In accordance with the present invention, a screen
assembly is provided which has screening material (any
known in the prior art, any described herein, any number
of layers either connected together or not) secured over
a screen assembly support or frame with space maintenance
apparatus on the bottom of the screen assembly to fill
the gap between the bottom of the screen assembly and the
top of screen assembly mounting structure to maintain the
screen assembly in contact with the mounting structure
and to inhibit or prevent inordinate flexing of the
screen assembly.
Figures 9A to 9B show a screen assembly support 400
in accordance with the present invention which has two
ends 401, 402 spaced apart by two sides 403, 404. The
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screen assembly 400 as shown is upside down with its
bottom shown in Figure 35A. Two spaced-apart cross-
members 405, 406 extend between the two ends 401, 402 and
two optional spaced-apart cross-members 407, 408 extend
between the cross-members 405, 406. (It is within the
scope of this invention to use one, two, three, four or
more of the cross-members 405 and/or cross-members 407).
The ends, sides, and/or cross-members may be solid or
they may be hollow. As shown in Figure 9C hollow tubular
members are used for the support 400 (as is common in
supports for screen assemblies for vibratory separators
and shale shakers).
As shown in Figure 9B space maintainers 411, 412 are
affixed to bottom surfaces of the cross-members 405, 406
to contact a mounting structure or deck and to maintain
contact between a screen assembly with a support 400 and
a deck or mounting surface of a vibratory separator or
shale shaker. As shown in Figure 9C, the space
maintainer 411 is hollow and is like the previously
described seal members 311 to 314. Any seal members
disclosed herein may be used for the space maintainers
411, 412 (and as may be any space maintainer disclosed
herein). In one aspect the space maintainers 411, 412
are made of nitrile material. To reduce flexing of a
screen assembly, in one aspect, e.g. as shown in Figure
9C, the base 414 of a space maintainer is as wide as a
part to which it is secured A hollow space 412 allows a
curved part 413 to flex to maintain contact with a
mounting structure.
The space maintainers 411, 412 (and any space
maintainer in accordance with the present invention) may
be secured to the bottom of a frame or support as are any
seals or seal members described herein and/or with
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screws, staples, brads, rivets and/or releasably
cooperating hook/loop fastener material. In one aspect
the space maintainers are secured to the bottom of cross-
members of the frame or support with glue or adhesive.
Figures 10A to 10E illustrate a screen assembly
support 420 like the screen assembly 400, Figure 9A, and
like numerals indicate like parts Seal members 401a,
402a, 403a and 404a are like the seal members 311 - 314,
Figure 1A and may be as wide as the seal members 311 -
314 but as shown are as wide as the support part to which
they are secured. Figure 1OF illustrates an alternate
embodiment for the cross-member 406 (and also for the
cross-member 405) in which a space maintainer 460 (like
the space maintainer 411 in materials and cross-sectional
dimensions or like any space maintainer disclosed herein)
has ends 461, 462 which terminate a distance d from seals
401a, 402a, respectively, so that the space maintainer
460 does not inhibit sealing of the seals 401a, 402a.
Such length and spacing may be used with any space
maintainer in accordance with the present invention.
Figures 11A and 11B illustrate a screen assembly
support 430 in accordance with the present invention
which is like the support 400, Figure 9A and like
numerals indicate like parts. Although it is within the
present invention to provide a space maintainer for each
cross-member of a screen assembly support, it is also
within the present invention to provide only one cross-
member with a space maintainer. It is also within the
present invention to provide a space maintainer which is
as long as a cross-member or which is shorter (e.g. in
certain aspects between four and thirty inches long) than
a cross-member. It is also within the scope of the
present invention to provide a cross-member with two,
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three, four or more spaced-apart space maintainers.
Space maintainers in accordance with the present
invention may be made of urethane (e.g. 80 to 90
durometer hardness) or of nitrile rubber material.
As shown in Figures 11A and 11B, a space maintainer
439 (e.g. like the space maintainers 411, 412, Figure 9A
except in length relative to the side 403) is secured to
a bottom of the cross-member 406. In certain aspects the
space maintainer 439 is between 10cm and 76cm (four and
thirty inches) long. It is within the scope of the
present invention to provide a similar space maintainer
on the cross-member 405. As shown in Figure 11C it is
within the scope of the present invention to provide a
plurality of spaced-apart space maintainers 436 - 438
(e.g. like any space maintainer discussed herein) on a
cross-member 435 (e.g. like any cross-member discussed
herein) of a screen assembly.
159. Although they are not equivalent to space
maintainers as in Figures 9A - 11C, a space maintainer
440 in accordance with the present invention may be
secured to a bottom of a screen assembly support cross-
member 441 by friction fit and/or with a suitable glue or
adhesive, e.g. "Super Glue."
The screen support may be of the type disclosed in
PCT Publication Number WO 01/76719 (which discloses,
inter alia a "UNIBODY" screen support) and provided with
space maintainers as disclosed herein on the cross-
members or ribs. Further, space maintainers as disclosed
herein may be arranged on the truss-like cross-members
and folded leaves disclosed in PCT Publication Number WO
2004/035231
The seals for sealing between screens may be any
suitable seal may be used [and, in one aspect, a seal as
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disclosed in U.S. Patent 6,443,310 B1 issued Sept. 3,
2003; in WO 2004/069429; or in WO 2004/035232; or in WO
2004/035233 -both said patent and all said applications
incorporated fully herein for all purposes].
It has been recognized that in some vibratory
separators employing screening assemblies employing
supports (or frames) made of relatively rigid material
(e.g., hollow tubular mild steel with a square cross-
section and a side measuring about 3/4" with a wall
thickness of about 1/8") that an effective seal between
an edge or side of the support and part of a bed, basket
or mounting structure of the vibratory separator is not
achieved. In some aspects, two spaced-apart sides of a
screen assembly are secured in place by edge mounting
structure, wedge structures, or inflated bladders which
push down on or wedge in the two spaced-apart sides.
With a relatively rigid screen support, such mounting can
result in insufficient flexing of the support so that
sides of the support (not the sides contacted by the
wedges or bladders) are not effectively sealed against
the bed, etc., (or against a seal member on a bed, etc.)
resulting in unsealed areas between the bed and the
support through which pieces of drilled cuttings or other
solids (which would normally move over and off the top of
the screen assembly) can move, i.e., move through the
open unsealed area (rather than as intended off the top
of the screen for collection) and fall into a sump or
reservoir (which is intended ideally to receive only
filtered drilling fluid) from which they can be recycled
back down into the wellbore negatively affecting drilling
efficiency. One specific vibratory separator in which
this problem may be encountered depending on the screen
assemblies used is disclosed in U.S. Patent 5,641,070
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issued June 24, 1997, incorporated fully herein for all
purposes.
In one aspect this ineffective sealing problem is
addressed in accordance with the present invention by
modifying a typical rigid prior art support for a screen
assembly by removing cross-members that extend in one of
two general directions between one or the other pair of
two spaced-apart sides thereof, so that the remaining
cross-members are all positioned so that they lie
generally in the direction of material flow on the screen
assembly when it is in use on a vibratory separator or
are all transverse to such flow direction; i.e., cross-
members are present in certain of the methods in
accordance with the present invention in only one
direction, not both; and, in certain aspects, there are
two, three, four, five, six or more of such cross-members
which, in one aspect, are equally spaced-apart across the
screen assembly and from the sides thereof. It is to be
understood that the structure shown in these figures may
be modified so that there are any desired number of
cross-members and, in one particular aspect, two or five
such cross-members equally spaced-apart across the
support.
It is also desirable that as the solids, etc. move on top
of the screens that, as viewed from above, the solids are
uniformly and evenly distributed across the width of the
screen assemblies. With a screen assembly with a prior
art support as shown in Figure 12 with cross-members
transverse to the length of the screen and cross-members
connecting between a screen side and a cross-member
(cross-members that in use would be generally parallel to
the direction of material flow on the tops of the screen
assemblies in Figure 24), "dead zones" develop on top of
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the screen assemblies above the transverse cross-members
and solids do not move in these dead zones or do not move
as readily in these dead zones, creating a relatively
larger mass of solids that moves along areas of the tops
of the screen assemblies not above these cross-members
resulting in a non-uniform flow of solids on the tops of
the screens. When there are transverse cross-members
extending from one side of the support to the other,
these dead zones can also extend from one side of the
screen assembly to the other. Undesirable masses of
solids in these dead zones, masses with more liquid in
them than in material in adjacent areas on top of the
screen assembly, may not have as much fluid removed from
them if the dead zones were not present. By removing
transverse cross-members and using a support, e.g. as in
Figures 13A and 23A or 25A or 26, the occurrence and/or
size of these dead zones is reduced and greater
processing efficiency is achieved. The relatively large
masses of material moving on the top of a screen assembly
with the prior art support can increase wear of the
screen mesh and contribute to a shorter useful screen
assembly life. If a screen assembly with the prior art
support has these undesirable relatively large masses of
solids moving on top of it, and the screen assembly is
ineffectively sealed to the shaker's basket, deck, or bed
for supporting screen assemblies, the problem with solids
moving through an unsealed area into the sump is
exacerbated.
The present invention, therefore, in at least some,
but not necessarily all embodiments, provides a method
for treating material with a vibratory separator, the
method including introducing material to be treated to a
vibratory separator, the vibratory separator as any
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described herein in accordance with the present
invention. Such a method may have one or some (in any
possible combination) of the following: wherein the
vibratory separator is a shale shaker and the material is
drilling fluid with drilled material therein; and/or
wherein the frame has at least one hole for receiving an
upwardly projecting member projecting upwardly from the
mounting structure of the vibratory separator, the method
further including installing the at least one screen
assembly so that the upwardly projecting member is
received in the at least one hole.
